This investigation is concerned with experimentally induced fat embolism in laboratory animals. We shall use labelled triglycerides which we have found to localize in the vascular bed of the lungs of mice. We shall study the distribution of injected lipids, their metabolism, kintics and lipases involved in their hydrolysis. Drugs affectin lipases, such as sulfated polysaccharides, will be examined on these parameters for their quantitative actions. Histological sections will be done on selected lungs. The results of this research will yield scientific data on the metabolic fate of pulmonary fat emboli and suggest a fundamental basis for rational drug treatment of this frequently lethal syndrome.